Feat: implement client side functionality for user follow feature

src/pages/api/users/[id]/follow-user.ts

@@ -0,0 +1,81 @@
+import { UserExtendedNextApiRequest } from '@/config/auth/types';
+import NextConnectOptions from '@/config/nextConnect/NextConnectOptions';
+import getCurrentUser from '@/config/nextConnect/middleware/getCurrentUser';
+import validateRequest from '@/config/nextConnect/middleware/validateRequest';
+import ServerError from '@/config/util/ServerError';
+import DBClient from '@/prisma/DBClient';
+import findUserById from '@/services/User/findUserById';
+
+import APIResponseValidationSchema from '@/validation/APIResponseValidationSchema';
+
+import { NextApiResponse } from 'next';
+import { createRouter } from 'next-connect';
+import { z } from 'zod';
+
+interface GetUserFollowInfoRequest extends UserExtendedNextApiRequest {
+  query: { id: string };
+}
+
+const router = createRouter<
+  GetUserFollowInfoRequest,
+  NextApiResponse<z.infer<typeof APIResponseValidationSchema>>
+>();
+
+const followUser = async (
+  req: GetUserFollowInfoRequest,
+  res: NextApiResponse<z.infer<typeof APIResponseValidationSchema>>,
+) => {
+  const { id } = req.query;
+
+  const user = await findUserById(id);
+  if (!user) {
+    throw new ServerError('User not found', 404);
+  }
+
+  const currentUser = req.user!;
+  const userIsFollowedBySessionUser = await DBClient.instance.userFollow.findFirst({
+    where: {
+      followerId: currentUser.id,
+      followingId: id,
+    },
+  });
+
+  if (!userIsFollowedBySessionUser) {
+    await DBClient.instance.userFollow.create({
+      data: { followerId: currentUser.id, followingId: id },
+    });
+
+    res.status(200).json({
+      message: 'Now following user.',
+      success: true,
+      statusCode: 200,
+    });
+
+    return;
+  }
+
+  await DBClient.instance.userFollow.delete({
+    where: {
+      followerId_followingId: {
+        followerId: currentUser.id,
+        followingId: id,
+      },
+    },
+  });
+
+  res.status(200).json({
+    message: 'No longer following user.',
+    success: true,
+    statusCode: 200,
+  });
+};
+
+router.post(
+  validateRequest({ querySchema: z.object({ id: z.string().cuid() }) }),
+  getCurrentUser,
+  followUser,
+);
+
+const handler = router.handler(NextConnectOptions);
+
+export default handler;

src/pages/api/users/[id]/is-followed.ts

@@ -0,0 +1,71 @@
+import { UserExtendedNextApiRequest } from '@/config/auth/types';
+import NextConnectOptions from '@/config/nextConnect/NextConnectOptions';
+import getCurrentUser from '@/config/nextConnect/middleware/getCurrentUser';
+import validateRequest from '@/config/nextConnect/middleware/validateRequest';
+import ServerError from '@/config/util/ServerError';
+import DBClient from '@/prisma/DBClient';
+import findUserById from '@/services/User/findUserById';
+
+import APIResponseValidationSchema from '@/validation/APIResponseValidationSchema';
+
+import { NextApiResponse } from 'next';
+import { createRouter } from 'next-connect';
+import { z } from 'zod';
+
+interface GetUserFollowInfoRequest extends UserExtendedNextApiRequest {
+  query: { id: string };
+}
+
+const router = createRouter<
+  GetUserFollowInfoRequest,
+  NextApiResponse<z.infer<typeof APIResponseValidationSchema>>
+>();
+
+const checkIfUserIsFollowedBySessionUser = async (
+  req: GetUserFollowInfoRequest,
+  res: NextApiResponse<z.infer<typeof APIResponseValidationSchema>>,
+) => {
+  const { id } = req.query;
+
+  const user = await findUserById(id);
+  if (!user) {
+    throw new ServerError('User not found', 404);
+  }
+
+  const currentUser = req.user!;
+
+  const userIsFollowedBySessionUser = await DBClient.instance.userFollow.findFirst({
+    where: {
+      followerId: currentUser.id,
+      followingId: id,
+    },
+  });
+
+  if (!userIsFollowedBySessionUser) {
+    res.status(200).json({
+      message: 'User is not followed by the current user.',
+      success: true,
+      statusCode: 200,
+      payload: { isFollowed: false },
+    });
+
+    return;
+  }
+
+  res.status(200).json({
+    message: 'User is followed by the current user.',
+    success: true,
+    statusCode: 200,
+    payload: { isFollowed: true },
+  });
+};
+
+router.get(
+  validateRequest({ querySchema: z.object({ id: z.string().cuid() }) }),
+  getCurrentUser,
+  checkIfUserIsFollowedBySessionUser,
+);
+
+const handler = router.handler(NextConnectOptions);
+
+export default handler;